Polyol ester basestocks are a known class of lubricant materials and find use, for example, in the lubrication of gas turbine engines. For example, U.S. Pat. No. 3,694,382 to Kleiman discloses an ester blend including esters of trimethylolpropane and dipentaerythritol formed from a mixture of aliphatic monocarboxylic acids. U.S. Pat. No. 4,049,563 to Burrous discloses a jet engine oil consisting of an ester of C.sub.4 -C.sub.12 monocarboxylic acids, certain types of polyols, and a soluble methylphenylpolysiloxane. Walker in U.S. Pat. No. 4,064,058 describes a grease basestock including a blend of a normally liquid pentaerythritol ester and a neopentylglycol ester. Warman in U.S Pat. No. 3,360,465 discloses synthetic ester lubricant compositions of mixed pentaerythritol esters. More recently, U.S. Pat. No. 4,826,633 to Carr describes an improved synthetic ester lubricant formed by reacting either trimethylolpropane or pentaerythritol with a mixture of certain aliphatic monocarboxylic acids.
Formulated polyol ester compositions which contain certain additive packages, to achieve certain desired properties and characteristics are also known. Typical additive packages are shown in U.S. Pat. Nos. 4,124,513 and 4,141,845, for example, which describe packages based on an alkylphenyl or alkarylphenyl naphthylamines, a dialkyldiphenylamine, a polyhydroxyanthraquinone, a hydrocarbylphosphate ester with an S-alkyl-2-mercaptobenzotriazole, or an N-alkyl-benzothiazole-2-thione. U.S. Pat. No. 4,440,657 describes another additive package comprising t-butylphenyl substituted phosphate and alkylamine compounds.